16 GPIO Terminal Block User’s Guide
Open Collector Input Interface
You can connect the input to an open collector interface of an
external device, which suggests that the grounds are tied together for
the two systems. Because the common ground can be a source of
input noise, follow good grounding practices for both the reader and
the input device.
The illustration shows the reader providing power to the pull-up
resistor for the open collector. Remove the jumper between the -Input
and Ground posts, and use it to short out the +12 V and +Input posts.
Open Collector Input Interface
Input
Input (< 6 mA)
Ground
Reader interface
12 V
RTN
Open collector
interface